1. Field of the Disclosure
This disclosure relates to footwear with interchangeable parts. Sandals such as thong-type flip-flop sandals are provided with anchoring posts at the front and near the side edges of a sole or platform, the posts having shafts with enlarged ends resembling nail heads. Different straps and strap configurations can be attached at the posts to produce alternative configurations for the sandal uppers, including variable ankle and instep strap arrangements and alternatives for shape, color and surface configuration.
2. Related Art
A simple form of sandal has a sole part that slightly exceeds the surface area occupied by the foot, and one or more strap or upper parts that are affixed to the sole part at spaced locations. The wearer's foot occupies a space between the upper (such as a strap) and the top surface of the sole. In different arrangements of shoes, the upper may define an open or closed toe and might or might not have sidewalls and a heel. However in sandals, the foot is generally exposed. Straps extend over the instep between spaced points to hold the shoe on the wearer's foot.
The sole can be a simple panel of constant thickness, possibly with laminated layers. In sandals known as flip-flops, a typical sole is a 2 cm thick lamination of rubber or plastic sheets. The sole alternatively can comprise a more rigid or durable material such as wood or leather. The sole can vary in thickness or shape, e.g., having a relatively thicker and/or higher heel part.
The upper of the shoe typically at least has a strap that extends laterally from attachment points at or near opposite edges of the sole. This strap can be wide or narrow. In flip-flop or thong sandals, there is also an attachment point at the front of the sole, spaced several cm back from the front edge, where one or more straps is affixed to the sole at a point located between the wearer's great toe and second toe. In this arrangement, there are typically two straps, each extending from the front attachment point to a point at or near a respective lateral edge of the sole, perhaps 8 or 10 cm rearward from the front edge of the sole. The two straps are typically provided in an integrally molded V-shaped strap element having three connecting points. At each connecting point, a shaft or post penetrates through at least an inner (upper) lamina of the sole and terminates in a flat disc-shaped plug having a larger diameter than the shaft or post. During assembly, the terminating plugs are forced through holes in the inner/upper sole layer. The plugs reside in counterbores that are cut or molded into the underside of the sole (in the underside of the inner/upper layer or in a lower laminated layer). The counterbores have a depth equal to the thickness of their respective discs, and anchor the ends of the straps. The plugs may be exposed on the underside of the sole, or the underside of the sole may have an additional laminated layer that covers the plugs.
In a basic form, the upper or thong portion consists of two straps joined together and attached to the sole at the point between the toes. The other ends of the straps are attached at the lateral edges of the sole, some distance back from the front attachment. The points of attachment in some configurations are forward of the wearer's ankle and in others are at the ankle or aft of the ankle. Some variations can be found, for example, in U.S. Pat. No. 3,290,802—Fukuoka, which has a cross-member connecting at midpoints of the straps; U.S. Pat. No. 3,336,683—Schellkopf or U.S. Pat. No. 4,051,610—Shigeji, which have ankle straps that can reside behind the ankle; and U.S. Pat. No. 7,540,098—Bask et al., wherein the straps can have plural sections and are affixed at their ends in alternative ways; etc.
Shoes and sandals are known wherein the upper part of a shoe or a part such as a strap forming an enclosure for the foot, is arranged to be detached so that the upper can be replaced with one of a different width or shape or color or surface configuration. U.S. Pat. No. 6,769,204—Phillips and U.S. Pat. No. 7,481,008—Lusk disclose thong sandals wherein the thongs are not removable but are adapted to receive interchangeable decorative covers, affixed adhesively atop the straps, and changed when the wearer chooses to adopt a different theme or color scheme.
Although attachment arrangements are generally known for shoe uppers, what still is needed is an effective way to provide detachable interchangeable uppers for thong-type flip-flop sandals. It is not practical to expect users to exchange the uppers of sandals by pulling out the anchoring plugs and mounting different uppers by forcing the plugs of the different uppers into position. Changing cover tapes on thong straps is superficial. What is needed is an effective way to anchor the uppers of thong sandals or similar footwear, that facilitates substantial changes, including changes in the configuration of the uppers, preferably not only as to surface decoration but also to vary the structural nature of the footwear, to increase or decrease the extent of coverage of the foot, and to open new opportunities for footwear styling.